THE BBC is working on a drama about the early days of Doctor Who to mark the hit show’s 50th anniversary.

The 90-minute film will examine how the show was brought to life, looking at the key figures in the sci-fi series, which first aired on November 23, 1963.

The one-off BBC2 story, called An Adventure In Space And Time, is being written by Doctor Who scriptwriter Mark Gatiss.

Details about casting – including who will play the actor who first starred as the Doctor, William Hartnell – will be confirmed next year.

The BBC won acclaim two years ago for its drama The Road To Coronation Street which looked at the birth of the ITV soap, coinciding with the programme’s half-century celebrations.

TV chiefs said the new programme would explore “all aspects” of the show and would cover “the many personalities involved in bringing the series to life”.

Gatiss said: “This is the story of how an unlikely set of brilliant people created a true television original. And how an actor – William Hartnell – stereotyped in hard-man roles became a hero to millions of children.

“I’ve wanted to tell this story for more years than I can remember. To make it happen for Doctor Who’s 50th birthday is, quite simply, a dream come true.”

Executive producer Steven Moffat, who is in charge of Doctor Who at the BBC, said: “The story of Doctor Who is the story of television, so it’s fitting in the anniversary year that we make our most important journey back in time to see how the Tardis was launched.”

The announcement comes as David Tennant refused to be drawn on whether he would make a return appearance as the Doctor to mark the programme’s anniversary.

Occasionally the many surviving incarnations of the Doctor have been brought together for storylines, beginning in 1973 when Hartnell, Patrick Troughton and Jon Pertwee were united for a story called The Three Doctors.

Tennant, who played the Time Lord from 2005 to 2010, said: “I cannot be drawn on anything. Who knows what will happen next year?

He told US TV programme Attack Of The Show: “I’m sure there are lots of plans being discussed in quiet rooms by men with long beards and grey hair.”